Package org.springframework.beans.factory.annotation

Class ParameterResolutionDelegate

java.lang.Object

org.springframework.beans.factory.annotation.ParameterResolutionDelegate

public final class ParameterResolutionDelegate
extends Object

Public delegate for resolving autowirable parameters on externally managed constructors and methods.

Since:

5.2

Author:

Sam Brannen, Juergen Hoeller

See Also:

• isAutowirable(java.lang.reflect.Parameter, int)
• resolveDependency(java.lang.reflect.Parameter, int, java.lang.Class<?>, org.springframework.beans.factory.config.AutowireCapableBeanFactory)

Method Summary

Modifier and Type	Method	Description
static boolean	isAutowirable(Parameter parameter, int parameterIndex)	Determine if the supplied Parameter can potentially be autowired from an AutowireCapableBeanFactory.
static Object	resolveDependency(Parameter parameter, int parameterIndex, Class<?> containingClass, AutowireCapableBeanFactory beanFactory)	Resolve the dependency for the supplied Parameter from the supplied AutowireCapableBeanFactory.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

isAutowirable

public static boolean isAutowirable(Parameter parameter,
 int parameterIndex)

Determine if the supplied Parameter can potentially be autowired from an AutowireCapableBeanFactory.

Returns true if the supplied parameter is annotated or meta-annotated with @Autowired, @Qualifier, or @Value.

Note that resolveDependency(java.lang.reflect.Parameter, int, java.lang.Class<?>, org.springframework.beans.factory.config.AutowireCapableBeanFactory) may still be able to resolve the dependency for the supplied parameter even if this method returns false.

Parameters:

parameter - the parameter whose dependency should be autowired (must not be null)

parameterIndex - the index of the parameter in the constructor or method that declares the parameter

See Also:

• resolveDependency(java.lang.reflect.Parameter, int, java.lang.Class<?>, org.springframework.beans.factory.config.AutowireCapableBeanFactory)

resolveDependency

@Nullable
public static Object resolveDependency(Parameter parameter,
 int parameterIndex,
 Class<?> containingClass,
 AutowireCapableBeanFactory beanFactory)
                                throws BeansException

Resolve the dependency for the supplied Parameter from the supplied AutowireCapableBeanFactory.

Provides comprehensive autowiring support for individual method parameters on par with Spring's dependency injection facilities for autowired fields and methods, including support for @Autowired, @Qualifier, and @Value with support for property placeholders and SpEL expressions in @Value declarations.

The dependency is required unless the parameter is annotated or meta-annotated with @Autowired with the required flag set to false.

If an explicit qualifier is not declared, the name of the parameter will be used as the qualifier for resolving ambiguities.

Parameters:

parameter - the parameter whose dependency should be resolved (must not be null)

parameterIndex - the index of the parameter in the constructor or method that declares the parameter

containingClass - the concrete class that contains the parameter; this may differ from the class that declares the parameter in that it may be a subclass thereof, potentially substituting type variables (must not be null)

beanFactory - the AutowireCapableBeanFactory from which to resolve the dependency (must not be null)

Returns:

the resolved object, or null if none found

Throws:

BeansException - if dependency resolution failed

See Also:

• isAutowirable(java.lang.reflect.Parameter, int)
• Autowired.required()
• SynthesizingMethodParameter.forExecutable(Executable, int)
• AutowireCapableBeanFactory.resolveDependency(DependencyDescriptor, String)